red eyeSummary

Methodology Score: 2/5                   
Usefulness Score:  2/5
Narayana S, et al.
Am J Med. 2015 Nov;128(11):1220-1224.e1.
This review study looked at the diagnostic accuracy of physical exam findings for serious causes of red eye and bacterial conjunctivitis; for red eye photophobia (direct, indirect and near synkinesis) and anisocoria had the highest LR, while for bacterial conjunctivitis complete redness of conjunctival membrane, observed purulent discharge and bilateral morning matting of the eyes had the highest LRs.  Overall the group felt this review paper was not helpful as it was not thorough enough in its literature search and many of the exam findings had insignificant LRs. 
By: Dr. Julia Traer

Epi lesson

For diagnostic tests, LR+ increases the post-test probability of a diagnosis and LR- decreases the post-test probability. LR values generally have this impact: a) large and conclusive (LR+ >10, LR- <0.1), b) moderate (LR+ 5 to10, LR- 0.1 to 0.2), c) small but important (LR+ 2 to 5, LR- 0.2 to 0.5), d) unimportant (LR+ 1 to 2, LR- 0.5 to 1). In emergency medicine, we are generally most interested in ruling out serious conditions and look for tests with very high sensitivity and very low LR-.

By: Dr. Ian Stiell